Identification of clonal T cells in the blood of patients with systemic sclerosis - Positive correlation with response to photopheresis

Objectives: To search for circulating clonal T-cell populations in patients with systemic sclerosis (SSc), and to determine whether T-cell clonality i n the blood predicts therapeutic response to photopheresis. Design: Analysis of clonal T-cell receptor gamma gene rearrangements before photopheresis treatment and blinded clinical evaluation of cutaneous respo nse to photopheresis in a case series. Setting: University hospital setting. Patients: Thirteen consecutive patients with SSc. Interventions: Photopheresis in 11 patients. Main Outcome Measures: Clonality of T cells in the blood before photopheres is, and clinical response to photopheresis. Results: Screening of blood samples from 13 SSc patients for clonal T-cell receptor gamma gene rearrangements revealed a monoclonal T cell population in 6 (46%) of 13 SSc patients. Clinical response to photopheresis in 11 pat ients was evaluated in a blinded manner using skin severity scores. Clonali ty of T cells appeared to be associated with a higher chance of response to photopheresis therapy, as 4 (67%) of 6 patients in the clone-positive grou p vs 1 (20%) of 5 in the clone-negative group experienced a clinically sign ificant response to treatment. Conclusions: A high proportion of patients with SSc have detectable expande d clonal T-cell populations in the peripheral blood, and such patients appe ar more likely to respond to photopheresis.